Alan Harris

Least Tern in East Sussex:
new to Britain and theWestern Palearctic
Barry Yates
Abstract A Little Tern Sternula albifrons with a distinctive ‘squeaky’ voice wasdiscovered in the tern colony at Rye Harbour, East Sussex, in June 1983. It returned
annually until 1992. Although it was dismissed initially as an odd Little Tern,comparison of sound recordings of the call with those of the North American form
S. (albifrons) antillarum, together with the noticeably greyer rump and central tailfeathers, led to the eventual realisation that it was one of the New World races ofLittle Tern, known as ‘Least Tern’. Research into the calls of all races of Little Terneliminated other possibilities and it was eventually accepted as an individual of theNorth American antillarum/athalassos/browni group. Although its distinctive
advertising call drew attention to the bird in flight, when silent it was not separablefrom the many Little Terns present. It was seen to display and present fish to Little
Terns, suggesting that it was a male, but there is no evidence that breeding took
place.

I

ntensive daily management of the Little
Tern Sternula albifrons breeding colony at
Rye Harbour Nature Reserve in East
Sussex led to the discovery, in June 1983, of
an individual small tern with an unusual call.
The call was so distinctive that it enabled thebird to be readily located within the throngof Little Terns, and it was soon nicknamed© British Birds 103 • June 2010 • 339–347‘Squeaker’. This bird returned to Rye
Harbour annually until 1992, and during thattime it was enjoyed by many birdwatchers.
Although it was not appreciated initially, thecall resembled that given by the North American race of Little Tern S. (albifrons) antillarum, known in North America as Least
Tern. Owing to uncertainties over the calls
339

Yatesbecome available to BBRC and BOURC. This
resulted in a protracted delay to the review
process, and it was not until 2006 that therecord was finally accepted as a Little Tern of
the North American antillarum/athalassos/
browni group (BOU 2006), and added toCategory A of the British List as a race ofLittle Tern.

Brian Small

given by other similar small terns, there wasdebate as to whether the bird really was a
Least Tern, or whether other races of Little
Tern, including the West African race S. a.
guineae, could give a similar call.
Although the call appeared to be indistinguishable from that of Least Tern, it took
several years for recordings of other small
terns, including that of S. a. guineae toFig. 1. Notes and sketches of the Rye Harbour Least Tern Sternula (albifrons) antillarum, June 1992.
340

British Birds 103 • June 2010 • 339–347

Least Tern in East Sussex: new to Britain
The discovery
Pam Knight, then assistant warden of Rye
Harbour NR, made the first detailed observation of ‘Squeaker’ on 14th June 1983 andincluded the following comments in her
notebook: ‘Squeaky-voiced tern – by behaviour a male – arrived about 5–6 days ago.
Favoured area at east end of West Beachcolony around nests 1 and 4 area. Observed
daily bringing in fish, approaching birds
from other nests and being chased off – quitepersistent. Also seen at Ternery Pool Ridges
colony but flew on down to West Beach.’
The warden, Richard Knight, wrote in the
Rye Harbour Nature Reserve Annual Reportfor 1983: ‘Interestingly, one Little Tern was
identifiable as an individual by its voice,which had a peculiar and very distinctive
squeaky sound. This bird arrived on about
8th June and over the following couple ofweeks took part in courtship flights, chasing
and display. It was observed several times
attempting to present fish to other birds inthe colony at West Beach but without success.
The bird, presumably a male, was notobserved to mate and was not seen after theend of June. One might surmise that its
abnormal voice was the reason for its failure
to attract a mate.’
Fortunately, the bird returned in 1984 andbecame a regular feature of the colony, where
it reappeared annually until 1992. It was not
until 1990 that interest in the bird reallybegan to gather momentum, with thegrowing realisation that the distinctive
squeaky call closely resembled recordings ofLeast Tern. Many birdwatchers visited the siteand made detailed notes and sketches,
including Brian Small whose notebook
details and sketches are reproduced below(fig. 1). I am not aware of any photographs
being taken of the bird.

Description
Overall, the bird was extremely similar to the
Little Terns in the colony. However, in overcast conditions the rump appeared noticeably grey (unlike the white rump shown by
Little Tern) and, when the tail was spread, theouter feathers were whiter than the central
tail feathers. Some observers noted a slightly
fuller-chested appearance and broader-based
wing structure, and the bird appeared very
British Birds 103 • June 2010 • 339–347

slightly smaller than Little Tern. It wasreportedly seen to attempt to copulate with afemale Little Tern on at least one occasion.
The distinctive squeaking call was the‘advertising’ call of a male, typically heard as
it flew through the colony. It was transcribedas ‘pudee pudoo’ or ‘puedeek puedeek’ with atone similar to that of Oystercatcher
Haematopus ostralegus and very different
from the grating calls of Little Tern.
Brian Small, who visited the reserve on
19th and 20th June 1992, made the following
observations: ‘Throughout the two days I
spent at the colony, it was pretty elusive, particularly on 20th, when it made only a coupleof brief visits to the Little Tern colony; it was
harassed by the Little Terns, which drove it
off. In direct comparison with Little Tern, I
got the impression of the tail being“slimmer” and “finer”, and held to a point
more frequently. On the ground, the tip of
the tail seemed to reach the wing-tip (oralmost so); at times it looked slimmer-bodied
than Little. In flight, mantle, scapulars,
upperwing-coverts, most of the remiges,
uppertail-coverts and “middle tail” noted as
an evenly toned pale grey, slightly lighter on
the outer secondaries and outer rectrices.
When perched, it was noted as having greyer
remiges than Little, which gave it an evenly
toned upperpart appearance. In comparison,
Little was noted as having a white rump andtail, though I did see at least one Little Ternwith a slight pale grey shade on the centre of
the upper rump. The most distinctive feature
was the call, described as a squeaky,“pudeek… pudeek”, together with miscellaneous chattery notes.’

Identification as Least Tern
Plumage features are of little value in the separation of Little and Least Terns. Olsen &Larsson (1995) stated that Least Tern is, generally speaking, identical to Little Tern, butshows a grey rump and central part of the tailwhich is concolorous with the back. Proportionately, it is slightly smaller, with shorter
legs, a relatively slimmer bill and, when adult,
generally longer tail streamers. In detail, thecentral four pairs of tail feathers (T1–4) are
grey, T5 is grey or with a white inner web,and T6 is white with a grey tinge to thecentral and outer parts of the inner web
341

Yates(although sometimes white). Identification,
therefore, relies heavily on vocal differences.
The first indication that the bird could be
antillarum came during the winter of
1985/86, when Richard Knight and John
Trowell were listening to the Audubon Sound
Recording of Least Tern. They realised
immediately that the advertising call of Least
Tern was a very close match to the call of‘Squeaker’. In June 1986, I borrowed soundrecording equipment and made a recording of
the distinctive call, which can be heard atwww.wildrye.info/media/audio. A copy of therecording was sent to Barbara Massey, anauthority on terns in North America, who
replied on 21st January 1990 with thefollowing comments: ‘The new cassette is a
big improvement, and allows me to say
without hesitation that your “squeaky” ternsounds like Sterna antillarum. Isn’t thatastonishing! You said this “stray” never founda mate. I presumed back in 1973 that thedifference in calls would prevent antillarum
and albifrons from mating, if ever they shouldcome together. Your observations haveconfirmed this, and the splitting of the two,based mainly on vocalisations, has been
justified.’
Howard Taffs arranged for the recorded
calls to be converted to sonograms by Dr
Clive Catchpole at University of London.
These were included in a published summaryof the occurrence (Yates & Taffs 1990), which
discussed the overall similarity of the soundspectrograms of the Rye Harbour ‘Squeaker’
and the Audubon recording of Least Tern.
This led the authors to conclude that the Rye
Harbour bird was antillarum.
Prior to 1990, there was little interest in
the bird beyond its unusual call, which
revealed its presence. During that year,
however, there was a growing awarenessamong birders that the bird was Least Ternand many visited to see and hear it. Theinterest peaked after the publication of Yates& Taffs (1990) and the bird was heard regularly within the colony during the 1990–92
breeding seasons. Despite its distinctive call,it was almost impossible to locate whensilent, and some birders had to make multiple visits before finally being certain thatthey had seen the right bird!

342

Summary of annual occurrences
Following its initial discovery in 1983,‘Squeaker’ was relocated in the Rye Harbour
Little Tern colony each year until 1992. Identification essentially relied upon hearing its
distinctive call, but as the significance of thiswas not appreciated during the earlier years,
its presence may have gone unrecorded ondates before, during or after those listed
below:
1983 – about 8th June to 5th July
(Little Tern colony size 67 pairs).
1984 – present as ‘Squeaker’ but dates notnoted (66 pairs).
1985 – heard only on 30th May (76 pairs).
1986 – heard only on 22nd May (70 pairs).
1987 – present as ‘Squeaker’ but dates notnoted (55 pairs).
1988 – heard only on 23rd May and 8thJune (55 pairs).
1989 – heard on four dates between 28th
May and 24th June (55 pairs).
1990 – heard regularly between 21st May
and 12th July (30 pairs).
1991 – heard regularly between 25th May
and 13th July (40 pairs).
1992 – heard regularly between 24th May
and 8th July (48 pairs).

Record evaluation
Once it was widely acknowledged that thecalls given by ‘Squeaker’ were indistinguishable from those of North American Least
Terns, the record was submitted to BBRC.
The record was accepted, largely based on thecall, and the file was passed to BOURC as apotentially new taxon for the British List.
Although the recorded calls appeared to ruleout all other options, BOURC expressed
concern that extralimital races of Little Tern
could occur in Britain, and that the call ofthese needed to be investigated before therecord could be reviewed. In addition to thenominate race of Little Tern, which breeds in
Europe, North Africa and western Asia, twoother Old World races of Little Tern arerecognised: S. a. guineae breeds in West andcentral Africa, and S. a. sinensis breeds ineastern Asia and the northern and eastern
coasts of Australia.
In particular, the calls of West African S. a.
guineae, the extralimital race breeding closest
British Birds 103 • June 2010 • 339–347

10.5
9
7.5
6
4.5
3
1.5
0
0

10.5
9
7.5
6
4.5
3
1.5
0

0.5

0

1

0.5

1.5

1

2

1.5

2

2.5
time (sec)3

2.5
time (sec)

3.5

3

4

3.5

4.5

4

4.5

frequency kHz

Fig. 2. Advertising calls of Little Tern Sternula a. albifrons, Dorset, June 1977
(Kettle & Ranft 1992). Note the short duration of each call, mainly within
the frequency range of 1.5–6.5 kHz.
10.5
9
7.5
6
4.5
3
1.5
0
0

0.5

1

1.5

2

2.5
time (sec)

3

3.5

4

4.5

Fig. 3. Flight calls of Little Tern Sternula a. albifrons, France, May(Chappuis 2000). Each call is of longer duration than the advertising call.

frequency kHz

to Europe, were
unknown at thetime. Until recordings became available,
BOURC
considered that noformal decision
could be made.
Efforts were madeto obtain recordingsof as many of thesmaller terns as
possible, and theseproved to be largely
successful. Sonograms were made of
the advertising callsof Little and Least
Terns (figs. 2–8), as
well as many of theother smaller terns,by George Sangsteronbehalfof
BOURC, and compared with those of
the Rye Harbour
bird (fig. 9).
Having finallyestablished that thecalls of the Rye
Harbour ‘Squeaker’
differed from thoseof all other races ofLittle Tern, but
matched those of
Least Tern, BOURC
accepted the identification as Least Tern
(BOU 2006). Notethat in 1991 the bird
was present at Rye
Harbour from 25th
May to 13th July, but
was not heard from29th June to 1st July,when a bird giving
the same call was
reported at Colne
Point, Essex. It
seems likely that thesame bird was
involved in bothsightings.

frequency kHz

Least Tern in East Sussex: new to Britain

10.5
9
7.5
6
4.5
3
1.5
0
0
10.5
9
7.5
6
4.5
3
1.5
0

0.5

0

0.5

1

1

1.5

2

2.5
time (sec)

1.5

2time (sec)

2.5

3

3.5

3

3.5

4

4.5

4

Fig. 4. Unknown call type of West African breeding Little Tern Sternula
albifrons guineae, Langue de Barbarie, Senegal, 9th June 2001 (V. Bulteau &D. Vangeluwe, IRSNB, unpublished recording). The frequency range of guineae
is much tighter than that of calls given by nominate Little Tern in Europe, andis typically restricted to 3.5–6.0 kHz.

British Birds 103 • June 2010 • 339–347

343

Yatesfrequency kHz

frequency kHz

frequency kHz

frequency kHz

inthefield.
The two coastal
breeding
races
remain common
and widespread,but the inland
breeding popula0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
tion is endangered.
time (sec)
The race S. a.
Fig. 5. Calls given by male Little Tern of Asian race Sternula albifrons sinensis
antillarum
breedswhile pursuing a female, Japan, June (Ueda 1998). Although similar inonthe
Atlantic
frequency to those given by the nominate race, they are distinctly longer
coast of Northand given at more regular intervals.
America,from
10.5
Maine south along9
the east and south
7.5
coasts of the USA,6
4.5
and also occurs
3in Bermuda, the
1.5Caribbean
and
0
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Venezuela. The race
time (sec)S. a. browni breeds
Fig. 6. Advertising calls of Least Tern Sternula (albifrons) antillarum, New York on the Pacific coast,state, USA, June (Elliott 1997).
from central California south to10
western Mexico.
8
Two other sub6
4species are some2
times delineated,
0
0.5
1
1.5
2
2.5
3
3.5
4
S. a. mexicana andtime (sec)S. a. staebleri from
Fig. 7. Presumed advertising calls of Least Tern Sternula (albifrons) antillarum, the Gulf of CaliAudubon Sound Guide. Calls are given at intervals of approximately one
fornia south along
second and lack the harmonics shown by most Little Terns. Instead they
the Pacific Coast
appear as a distinct ‘M’ shape with a plateau at c. 4 kHz.
to Oaxaca and
Chiapas, but are10less widely recog8
nised (Thompson
64
et al. 1997; Dick2
inson2003).
0
0.5
1
1.5
2
2.5
3
3.5
Finally, the race S.
time (sec)a. athalassos, which
Fig. 8. Presumed advertising calls of Least Tern Sternula (albifrons) antillarum, breeds on the
Audubon Sound Guide. Calls are more complex and given more frequently
inland rivers of thethan those shown in fig. 7, within a frequency range of 3–4 kHz and with a
Mississippi River
plateau at c. 4 kHz. Note the almost complete absence of harmonics
drainage basin,compared with Little Tern.
including the MisDistribution and status
souri and Yellowstone Rivers, north toLeast Tern breeds along the coasts of North
Montana, was listed as endangered by the US
America, and also along major rivers andFish and Wildlife Service in 1985.
inland waterways. At least three subspecies
Northern birds are migratory, wintering
are recognised, these being morphologicallyto the south of the breeding range, mainly invery similar and differences between themCentral America and south to northern
are slight; they cannot be reliably separated
Brazil.
10.5
9
7.5
6
4.5
3
1.5
0

344

British Birds 103 • June 2010 • 339–347

Least Tern in East Sussex: new to Britain
Taxonomy

ecology. He gave little justification for his
decisions on subspecies. For example, in asingle sentence he noted that S. a. antillarum
was analogous to the European form butwith the rump and tail feathers grey, like theback.
Massey (1998) highlighted the value of theadvertising call as a tool for species separation, this being particularly valuable for mateidentification and chick–parent recognitionin mixed species colonies. She commented
that had Hartert appreciated the value of
vocalisations and behaviour in delineating
tern species, the lumping of Old World and
New World forms probably would have been
avoided. Massey used the distinctive vocalisations of different forms to justify the recognition of North American antillarum as a
species distinct from other taxa in the Old
World Little Tern complex. In addition, Pyleet al. (2005) presented evidence for theapparent assortative mating of Little andLeast Terns on Midway Atoll, in the Northwestern Hawaiian Islands.
Work on DNA sequencing (Bridge et al.
2005) has subsequently provided support for
Massey’s views, and demonstrated thatseveral of the smaller terns that were formerly included within the larger genus Sterna

Massey (1998) provided a useful summary of
the changes in small-tern taxonomy whichhave had a profound effect upon the(mis)understanding of species limits within
the Little Tern complex. Prior to 1915, nofewer than 19 species of very similar smalltern were recognised, many of which referredto the same taxon. Then, during a period
when lumping of the large number of species
described during the nineteenth and earlytwentieth centuries became fashionable,
Hartert (1921) undertook a major revision of
the terns. He absorbed the genus Sternula
within Sterna, and the number of species ofsmall terns was reduced to just one, Little
Tern, with five races (albifrons, saundersi,
sinensis, antillarum and browni; athalassos
was not described until 1942). No fewer than
12 taxa that previously had been treated as
distinct species were now not even recognised as races of Little Tern, and became synonyms of albifrons or sinensis. Hartert’s
revision was based upon comparisons ofmorphology and distribution. His description of S. a. albifrons, which extended to justover one page, encompassed adult breedingplumage, ranges of adult measurements,
juvenile plumage, distribution, and breeding

frequency kHz

10

a

8
6
4
2
0

frequency kHz

10
8

0.5

1

1.5

2
time (sec)

2.5

3

3.5

b

6
4
2
2

2.5

3
time (sec)

3.5

Fig. 9. ‘Advertising’ calls of ‘Squeaker’ recorded within the Little Tern Sternula albifrons colony at
Rye Harbour Nature Reserve, East Sussex, by the author. Although most calls visible here are given
by Little Terns, the distinctive ‘M’ shape to the call of ‘Squeaker’ closely matches that of the Least
Terns S. (albifrons) antillarum shown in figs. 7 and 8. In 9a, this can be seen at 0.5 s, 1.5 s, 2.5 s(although a Little Tern is calling simultaneously at this time) and 3.5 s. The interval between calls isapproximately one second and closely matches the time interval between calls of the Least Tern infig. 7. In fig. 9b, Squeaker calls at 2.2–2.3 s amid Little Terns, followed by rapid calls of Little.
British Birds 103 • June 2010 • 339–347

345

Yatesrepresent a distinct grouping. They established a 5.0% sequence divergence between
albifrons (albeit from an Australian sample)
and North American antillarum. Samples ofalbifrons from Europe and elsewhere, andSaunders’s Tern S. saundersi, which they also
recognise as a different species from Little
Tern, were not included in this study. Among
their recommendations was the treatment ofLittle Tern and Least Tern as distinct species
and the inclusion of seven species of smalltern within the genus Sternula: Little Tern,
Least Tern and Saunders’s Tern, together with
Fairy Tern S. nereis (Australia), Damara Tern
S. balaenarum (southwest Africa), Yellowbilled Tern S. superciliaris (eastern SouthAmerica) and Peruvian Tern S. lorata(Ecuador to northern Chile). Based uponthese findings, recognition of the New World
Least Tern as a species distinct from Old
World Little Tern has been adopted by AOU(Banks et al. 2006). BOURC has not yet
accepted this treatment, pending ongoing
genetic analyses of albifrons from western
Europe, but has recognised the validity of thegenus Sternula for the small terns (Sangster et
al. 2005).
Acknowledgments
I would like to extend my thanks to Barbara Massey forher supportive comments made on the recorded calls of
the Rye Harbour tern, and to Brian Small for allowing me
to include excerpts from his notebook which support
the detailed description. Richard and Pam Knightprovided observations from their field notebooks.
Howard Taffs kindly made arrangements with Dr Clive
Catchpole at University of London for sonograms to bemade from the recordings. I am also grateful to BOURC,
who obtained comparative sound recordings of thevarious smaller terns, which ultimately proved to be
essential for establishing the identity of the Rye Harbour
bird. Steve Dudley kindly accessed the BOURC archiveand copied the sonograms that appear in this paper.

References
Banks, R. C., Cicero, C., Dunn, J. L., Kratter, A. W.,
Rasmussen, P. C., Remsen, J. V., Jr., Rising, J. D., &Stotz, D. F. 2006. Forty-seventh supplement to theAmerican Ornithologists’ Union Check-list of North
American birds. The Auk 123(3): 926–936.
Bridge, E. S., Jones, A. W., & Baker, A. J. 2005.
A phylogenetic framework for the terns (Sternini)inferred from mtDNA sequences: implications fortaxonomy and plumage evolution. MolecularPhylogenetics and Evolution 35: 459–469.
Chappuis, C. 2000. African Bird Sounds. Birds of North,West and Central Africa. Ecofac and NSA, London.
[15 CDs and booklet].
Dickinson, E. C. (ed.) 2003. The Howard and Moore
Complete Checklist of the Birds of the World. 3rd edn.
Christopher Helm, London.
Elliott, L. 1997. Field Guide to Bird Songs. Eastern Region.
Time Warner Audio Books, New York. [3 CDs andbooklet]Kettle, R., & Ranft, R. 1992. British Bird Sounds on CD.
British Library, London. [2 CDs and booklet]
Olsen, K. M., & Larsson, H. 1995. Terns of Europe andNorth America. Christopher Helm, London.
Pyle, P., Hoffman, N., Casler, B., & McKee, T. 2005.
Little and Least Terns breeding on Midway Atoll:
identification, range extensions, and assortative
breeding behaviour. North American Birds 55: 3–6.
Sangster, G., Collinson, J. M., Helbig, A. J., Knox, A. G., &Parkin, D. T. 2005. Taxonomic recommendations for
British birds: third report. Ibis 147: 821–826.
Thompson, B. C., Jackson, J. A., Burger, J., Hill, L. A.,
Kirsch, E. M., & Atwood, J. L. 1997. Least Tern Sterna
antillarum. In: Poole, A., & Gill, F. (eds.), The Birds ofNorth America. No. 290. The Academy of Natural
Sciences, Philadelphia, Pennsylvania, & AOU,
Washington DC.
Ueda, H. 1998. 283 Wild Bird Songs of Japan. Tokyo.
[3 CDs and booklet]
Yates, B. J., & Taffs, H. 1990. Least Tern in East Sussex –a new Western Palearctic bird. Birding World
3: 197–199.

Dr Barry Yates, Rye Harbour Nature Reserve, 2 Watch Cottages, Winchelsea Beach, East Sussex
TN36 4LU; e-mail Barry.yates@eastsussex.gov.uk

Editorial comment Bob McGowan, Chairman of BOURC, commented: ‘Two aspects of theRye Harbour Least Tern were particularly noteworthy. First, the identification was based
principally on the distinctive call of the returning bird, rather than on more conventional plumage
characteristics. Second, the BOURC file was pended for an uncharacteristically lengthy period asefforts were made to obtain audio recordings of calls of extralimital races of Little Tern.
‘The ten-year history of the bird returning to the Sussex colony is well documented. While therump of the Least Tern was reported as marginally greyer than that of Little Tern, it was thedistinctive advertising call that first drew it to notice. Barbara Massey subsequently confirmed
346

British Birds 103 • June 2010 • 339–347

Least Tern in East Sussex: new to Britainthat audio recordings were typical of Least Tern “advertising” call and a case for acceptance wasdrawn up.
‘BOURC recognised that the credentials for antillarum were strong, with the call recordings
conclusively ruling out nominate Little Tern. However, as extralimital races of Little Tern wereconsidered potential vagrants to Britain – the West African race S. a. guineae in particular – it was
crucial that these were eliminated. Importantly, the rump of guineae, though variable, may begreyish in some individuals. Obtaining relevant audio recordings became a rather protracted
business and a final decision was delayed for a number of years. Helped by George Sangster’sefforts, BOURC finally acquired the evidence needed to rule out other Old World taxa and theRye Harbour individual was accepted as having a North American origin, the actual race being
undetermined but of the antillarum/athalassos/browni group.’
Adam Rowlands, BBRC Chairman, added: ‘This record demonstrates the value of researching
the potential identification of vagrant individuals of rare races which may subsequently transpire
to represent separate species. This is an important element of the RIACT Sub-committee’s work
undertaken by current and former members of BBRC on behalf of the Committee (see Brit. Birds
99: 619–645), although this approach was adopted after the present record was considered andaccepted by BBRC. Such taxa may be extremely difficult to separate from more regularly occurring species on current knowledge, but the story outlined above illustrates how they may reveal
themselves in a vagrant context through key distinctions such as diagnostic vocalisations. Least
Tern, perhaps unfairly, received relatively low-key treatment when accepted as a new bird for
Britain and the Western Palearctic. It was included in the BBRC 2004 Annual Report (Brit. Birds
98: 661–662) as an unassigned representative of a complex of Nearctic races of the Little Tern.
‘Observers at Little Tern colonies would be well advised to keep an ear out for the possible
reoccurrence of this species in the UK and it is likely that this would spark significantly moreinterest amongst British and European birders than the Sussex bird did during the ten years it
returned to visit the Rye Harbour colony. Sharp-eyed observers are also reminded to check thetail coloration of any breeding-plumage Little Terns they encounter. A grey-tailed individual
would cause immediate interest.’

Conservation research news
Compiled by Arjun Amar, Guy Anderson,
Richard Gregory and Juliet Vickery
The impact of predation on birds is often thecentre of heated debate, particularly when
the prey are of economic or conservation
importance and/or the predator is a speciesof conservation concern. This month’s Conservation Research News focuses on threeimportant papers tackling this subject, allrecently published in the Journal of Applied
Ecology. The first deals with the issue of the
UK’s recovering Common Raven Corvus
corax population, and its possible effect on
populations of upland waders. Previously
summarised in BB (Brit. Birds 103: 254), thisstudy exonerates Ravens as the cause ofobserved wader declines, and provides no© British Birds 103 • June 2010 • 347–349

evidence to warrant overturning the decision
by Scottish Natural Heritage to refuse to
grant several licences requested in 2007 and2008 to control Raven numbers to protect
breeding waders.
Amar, A., Redpath, S., Sim, I., & Buchanan, G. 2010.
Spatial and temporal associations between
recovering populations of Common Raven Corvus
corax and British upland wader populations.
J. Appl. Ecol. 47: 253–262.

However, another study provides much moreevidence for the effects of other predators on
upland waders:347